This week I battled with an error from the OOB SQL MA for MIM 2016 (which I don’t think has changed at all from FIM 2010, and probably not earlier versions as well). The MA was working with a SQL database table on a server in another, non-trusting AD forest, and using Windows authentication. The table then got moved to yet another non-trusting forest and, when I tried to update the MA settings, I got:
Failed to retrieve the schema. Exception from HRESULT: 0x80231100
For those that just want to know the answer – it had something to do with clear text AD credentials being blocked, and the workaround was to create a SQL account and connect with that instead.